Writing electronic paper

ABSTRACT

Embodiments of the present invention are directed to systems and methods for writing on electronic paper (“e-paper”) and display platforms implemented with e-paper. In one aspect, a system for writing information to electronic paper includes a writing module and an erasing unit connected to the writing module. The erasing unit is configured to erase information stored in the electronic paper. The system also includes a writing unit connected to the writing module and is configured to write information to the electronic paper. Information is written to the electronic paper by orienting the writing module so that the electronic paper passes the erasing unit prior to passing the writing unit.

CROSS REFERENCE

This application is a Continuation of U.S. patent application Ser. No.12/792,301, filed Jun. 2, 2010, entitled “SYSTEMS AND METHODS FORWRITING ON AND USING ELECTRONIC PAPER”, and which is incorporated hereinby reference.

BACKGROUND

Electronic paper (“e-paper”) is a display technology designed torecreate the appearance of ink on ordinary paper. E-paper reflects lightlike ordinary paper and may be capable of displaying text and imagesindefinitely without using electricity to refresh the image, whileallowing the image to be changed later. E-paper can also be implementedas a flexible, thin sheet, like paper. By contrast, a typical flat paneldisplay does not exhibit the same flexibility, uses a backlight toilluminate pixels, and has to be periodically refreshed in order tomaintain the display of an image. Typical e-paper implementationsinclude an e-paper display and electronics for rendering and displayingdigital media on the e-paper, such as electronic books (“e-books”).However, the majority of the cost associated with these platforms liesin the electronics used to write on the e-paper, while the cost of thee-paper is considerably less.

Manufacturers and users of display platforms continue to seek costeffective systems and methods for writing on e-paper and a variety ofdisplay platforms using e-paper.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A shows a plan view of an example piece of electronic paper.

FIG. 1B shows a cross-sectional view of a portion of the electronicpaper, shown in FIG. 1A, along a line A-A.

FIGS. 2A-2D show four examples of microcapsule implementations ofelectronic paper.

FIG. 3 shows a side view and schematic representation of a first examplewriting system configured in accordance with one or more embodiments ofthe present invention.

FIGS. 4A-4B show a side view and a schematic representation of a secondexample writing system configured in accordance with one or moreembodiments of the present invention.

FIG. 5 shows a side view and schematic representation of a third examplewriting system configured in accordance with one or more embodiments ofthe present invention.

FIGS. 6A-6C show side views of three writing systems configured inaccordance with one or more embodiments of the present invention.

FIGS. 7A-7C show different views of a first example printing systemconfigured in accordance with one or more embodiments of the presentinvention.

FIGS. 8A-8C show different views of a second example printing systemconfigured in accordance with one or more embodiments of the presentinvention.

FIGS. 9A-9B show examples of cards configured with a strip of e-paperfor displaying information in accordance with one or more embodiments ofthe present invention.

FIG. 10 shows an isometric view of an electronic paper writing machineand a card configured in accordance with one or more embodiments of thepresent invention.

FIGS. 11A-11B show an example of the writing system configured to writeinformation to electronic paper strip of a card in accordance with oneor more embodiments of the present invention.

FIG. 12 shows a flow diagram of a method of writing information toelectronic paper in accordance with one or more embodiments of thepresent invention.

DETAILED DESCRIPTION

Embodiments of the present invention are directed to systems and methodsfor writing on electronic paper (“e-paper”) and display platformsimplemented with e-paper. The display platforms included, but are notlimited to, cards, posters, general signage, pricing labels, and anyother platforms upon which e-paper can be displayed and system andmethod embodiments of the present invention can be used to write on thee-paper. A general description of the configuration and operation ofe-paper is provided in a first subsection. A description of system andmethod embodiments for writing on e-paper and a description of displayplatforms implemented with e-paper are provided in a second subsection.

Electronic Paper

FIG. 1A shows a plan view of an example piece of e-paper 102 andincludes an enlargement 104 of a small portion of the e-paper 102. Theenlargement 104 reveals the e-paper 102 includes an array of embedded,spherical-shaped microcapsules 106. FIG. 1B shows a cross-sectional viewof a portion of the e-paper 102 along a line A-A, shown in FIG. 1A. Thecross-sectional view reveals an example multilayer structure of thee-paper 102, including a layer of the microcapsules 106 sandwichedbetween a transparent insulating layer 108 and a conductive ground layer110. As shown in FIG. 1B, the conductive ground layer 110 is disposed ona substrate 112. Depending on how the e-paper is used determines thethickness and composition of the various layers. For example, theinsulating layer 108 can be composed of a transparent dielectric polymerand can range in thickness from approximately 100 nm to approximately 14μm. The insulating layer 108 can also be composed of a material thatholds charges or is porous or semi-porous to charges and/or ions. Theinsulating layer 108 can also be composed of a first insulating layerand second patterned conductive layer. The microcapsules, described ingreater detail below, can have a diameter of approximately 50 μm, butmay also range in diameter from approximately 20 μm to approximately 100μm. The conductive ground layer 110 can be composed of a transparentconductive material, such as indium tin oxide, or an opaque conductivematerial and can have a thickness ranging from approximately 5 nm toapproximately 1 mm. Typically, the layers 106, 108, and 110 have a totalthickness of approximately 100 μm. The substrate 112 can be composed ofan opaque material or a transparent material and can range in thicknessfrom approximately 20 μm to approximately 1 mm, or the thickness can bemuch larger depending on the how the e-paper is used. For example, thesubstrate 112 can be composed of polyester, plastic, or transparentMylar. Also, the substrate 112 can be omitted and the layers 106, 108,and 110 can be mounted on a wall or a product chassis.

Ideally the insulating layer 108 serves as a wear protection layer forthe layer of microcapsules 106 and normalizes the e-paper surface,eliminating surface topography and blocking surface conduction paths onthe microcapsule surfaces. A variation on e-paper 102 includes the layerof microcapsules 106, the ground layer 110, and the substrate 112, butthe insulating layer 108 can be omitted.

The microcapsules 106 can be filled with one or more pigment particlesthat can be used to display images by looking at the e-paper 102 fromthe insulating layer 108 side, although typical e-paper is viewedthrough the substrate layer 112. For example, returning to FIG. 1A, themicrocapsules 106 in the microcapsule layer can be configured with whiteand black particles. Each microcapsule can form a black and white pixelor groups of adjacent microcapsules can form a black and white pixel.When white particles of a microcapsule are located near the insulatinglayer 108 the microcapsule appears white to a viewer, and when the blackparticles of a microcapsule are located near the insulating layer 108the microcapsule appears black to the viewer. For example, enlargement104 shows a thin vertical line 118 displayed in the e-paper 102 by anumber of microcapsules 114 with black particles located near theinsulating layer 108 surrounded by microcapsules 106 with whiteparticles located near the insulating layer 108. The microcapsules 106are designed to exhibit image stability using chemical adhesion betweenparticles and/or between the particles and the microcapsule surface. Forexample, the black and white microcapsules ideally can hold text andimages indefinitely without drawing electricity, while allowing the textor images to be changed later.

FIGS. 2A-2D show four examples of microcapsule implementations ofe-paper. In the example of FIG. 2A, each microcapsule includes blackparticles 202 and while particles 204 suspended in a transparent fluid206. The particles can be of opposite charges. For example, the blackparticles 202 can be positively charged particles and the whiteparticles 204 can be negatively charged particles. One or moremicrocapsules form a pixel of black and white images displayed on thee-paper 102. The black and white images are created by placing white orblack particles near the insulating layer 108. For example, themicrocapsules 210-212 with white particles located near the transparentinsulating layer 108 reflect white light and appear white to a viewer208. By contrast, the microcapsules with black particles located nearthe transparent insulating layer 108, such as microcapsule 214, appearblack to the viewer 208, corresponding to a black portion of the imagedisplayed on the e-paper 102. Various shades of gray can be created byvarying the arrangement of alternating microcapsules with white andblack particles located near the insulating layer 108 using halftoning.

In the example of FIG. 2B, each microcapsule includes black particles216 suspended in a white colored fluid 218. The black particles 216 canbe positively charged particles or negatively charged particles. One ormore microcapsules form a pixel of black and white images displayed onthe e-paper 102. The black and white images are created by placing blackparticles near or away from the insulating layer 108. For example, themicrocapsules 220-222 with black particles located away from thetransparent insulating layer 108 reflect white light, corresponding to awhite portion of an image displayed on the e-paper 102. By contrast, themicrocapsules with black particles located near the transparentinsulating layer 108, such as microcapsule 224, appear black to theviewer 208, corresponding to a black portion of the image displayed onthe e-paper 102. Various shades of gray can be created by varying thearrangement of alternating microcapsules with black particles locatednear or away from the insulating layer 108 using halftoning.

In the example of FIG. 2C, the e-paper 102 is configured as describedabove with reference to FIG. 2A, except the insulating layer 108 isconfigured with alternating blue, red, and green regions. Adjacent blue,red, and green regions form color pixels, such as color pixels 226-228.Color images are created by placing different combinations of white orblack particles near the insulating layer 108. For example, themicrocapsules of color pixel 227 with white particles located near thered and green regions of the transparent insulating layer 108 reflectred and green light from the e-paper which appear in combination as ayellow pixel of a color image observed by the viewer 208. Themicrocapsules of color pixel 226 have black particles located near thetransparent insulating layer 108 causing the color pixel 226 to appearblack to the viewer 208. Only one microcapsule of color pixel 228 haswhite particles located near the blue region of the transparentinsulating layer 108 reflecting blue light from the e-paper. Theinsulating layer 108 may also use other primary colors to create colorimages such as regions with yellow, magenta, and cyan. The insulatinglayer 108 may also includes spot colors, such as colors associated witha logo.

In the example of FIG. 2D, the e-paper 102 is configured as describedabove with reference to FIG. 2B, except the black particles of eachmicrocapsule are replaced by either blue, red, or green positively, ornegatively, charged particles, represented by differently shadedparticles in legend 230. Microcapsules with adjacent blue, red, andgreen particles form color pixels, such as color pixels 232-234. Colorimages are created by placing different combinations of coloredparticles near the insulating layer 108. For example, the microcapsulesof color pixel 234 with red and green particles located near theinsulating layer 108 reflect red and green light from the e-paper whichappear in combination as a yellow pixel of a color image observed by theviewer 208. The microcapsules of color pixel 232 have colored particleslocated away from the insulating layer 108 causing the color pixel 232to appear white to the viewer 208. Only one microcapsule of color pixel233 has red particles located near the insulating layer 108 reflectingred light from the e-paper.

The e-paper 102 and variations shown in FIGS. 2A-2D represent only ahandful of many different varieties of e-paper that is suitable for usewith the electronic paper writing systems and methods of the presentinvention. Other types of e-paper include electrophoretic paper, fieldinduced displays, or any other display surface activated by anelectrical field directed substantially perpendicular to the displaysurface.

For the sake of simplicity and brevity, writing systems and methodembodiments are described using the e-paper described above withreference to FIG. 2A. However, writing systems and methods are notintended to be limited in their application. The writing systems andmethods can be used to write to any type of e-paper, including any ofthe kinds of e-paper described above in the preceding subsection.

FIG. 3 shows a side view and schematic representation of an examplewriting system 300. The writing system 300 includes a writing module302, writing unit 304, and an erasing unit 306. The writing unit 304 anderasing unit 306 are connected to the same side of the writing module300 that faces the outer surface 308 of the insulating layer 108, withthe ion head 304 suspended above the surface 308. In the example of FIG.3, the writing unit 304 is an ion head and the erasing unit 306 can bean electrode that comes into close contact with, or can be draggedalong, the surface 308 in front of the ion head 304. The writing module302 can be moved in the direction 310 and the e-paper held stationary;or the e-paper 102 can be moved in the direction 312 and the writingmodule 302 held stationary; or the writing module 302 is moved in thedirection 310 and the e-paper 102 is simultaneously moved in theopposite direction 312.

In the example shown in FIG. 3, the black particles and the whiteparticles of the microcapsules are positively charged and negativelycharged, respectively. The erasing unit 306 erases any informationstored in the microcapsules prior to writing information with the ionhead 304. In the example shown in FIG. 3, as the e-paper 102 passesunder the writing module 302, the positively charged erasing unit 306can remove negatively charge ions attached to the surface 308. Thepositively charge erasing unit 306 also creates electrostatic forcesthat drive positively charged black particles away from the insulatinglayer 108 and attract negatively charged white particles toward theinsulating layer 108. For example, as shown in FIG. 3, as the positivelycharged erasing unit 306 passes over the surface 308 and approachesmicrocapsule 314, positively charged black particles of the microcapsule314 are repelled by the positive charge and driven away from theinsulating layer 108. By contrast, negatively charged white particlesare attracted to the erasing unit 306 and driven toward the insulatinglayer 108. When the erasing unit 306 reaches the microcapsule 316, thewhite and black particles of the microcapsule 314 are reversed and themicrocapsule 314 reflects white light.

FIG. 3 also reveals the writing operation performed by the ion head 304.In certain embodiments, the ion head 304 can be implemented as describedin U.S. Pat. No. 7,623,144, issued Nov. 24, 2009 to Hewlett-PackardDevelopment Company, L.P. The ion head 304 is configured and operated toselectively eject electrons, e−, 318 toward the insulating layer 108,when a region of the e-paper located beneath the ion head 304 is to bechanged from white to black. As the electrons reach the surface 308, thenegatively charged white particles are repelled and driven away from theinsulating layer 108, while the positively charged black particles areattracted to the negatively charged electrons and driven toward theinsulating layer 108. For example, as shown in FIG. 3, as the ion head304 passes over a portion of microcapsule 320 while ejecting electrons,the negatively charged white particles are repelled away from theinsulating layer 108 and the positively charged black particles aredriven toward the insulating layer 108. The electrons 318 can beabsorbed by the insulating layer 108 over the regions that are towritten to, or the electrons 318 can create ions that are absorbed byadhesion forces to the surface 308. In the case where ions are formed,it is believed that as the electrons 314 are ejected from the ion head304, the electrons interact with certain air molecules to formnegatively charge molecular ions 322 that attach to the surface 308. Forexample, it is believed that carbon dioxide in the air gap between theion head 304 and the surface 308 interacts with the ejected electrons toform a negatively charged carbon dioxide ion that attaches to thesurface 308.

Embodiments of the present invention are not limited to the ion head 304discharging electrons and the erasing unit 306 erasing information withpositive charges. The microcapsules 106 of the microcapsule layer can becomposed of negatively charged black particles and positively chargedwhite particles. In other embodiments, the ion head 304 can beconfigured to produce positively charged ions, which are absorbed to thesurface 308, and the erasing unit 306 can use negative charges to eraseinformation stored in the microcapsule layer of the e-paper 102. Inother embodiments, the writing unit can be any charge injection devicewith sufficient addressability and resolution. For example, the writingunit can be a plasma generating needle.

The negatively charged molecular ions attached to the surface 308 mayhelp to preserve information written to the e-paper 102. For example,FIG. 3 shows negatively charged molecular ions 324 attached to thesurface 308. The negatively charged ions 324 maintain the positivelycharged black particles located near the insulating layer 108 and thenegatively charged white particles located away from the insulatinglayer 108, preserving the information written to the e-paper 102.

When the e-paper 102 is handled by a person after writing, moisture,oils from the person's hands, and static electricity or tribo chargescarried by the person may alter the charge distribution over the surface308 or inside the layer 108. These charges may be large enough to causea redistribution of white and black particles in microcapsules. Forexample, the negatively charged ions may be moved along the surface 308switching portions or entire microcapsules from white to black. In orderto prevent image distortion due to tribo charges, or other chargechanging factors, which might occur due to handling, the particles, thefluid filling the microcapsules 106, and the insulating layer 108 can bedesigned to only move for charges and particles with a magnitudeexceeding the magnitude of the charges associated with handling. Forexample, the e-paper 102 could be designed so that charges and chargedparticles attached to the surface 308 or inside the layer 108 areredistributed with charges and electrical fields that can only begenerated during the writing phases.

In other embodiments, writing systems can also be configured with adischarging unit that removes ions from the surface 308 after the ionhead 304 has been used to write information into the layer ofmicrocapsules 106. The discharging unit can be an active or a passivecontact device that removes positive or negative charges from thesurface 308. For example, the discharging unit 402 can be composed ofcarbon conductive plastic or a conductive rubber and operated so thatcharges jump from the surface 308 onto the discharge unit. FIG. 4A showsa side view and schematic representation of an example writing system400. The writing system 400 is similar to the writing system 300described above except the writing system 400 includes a dischargingunit 402 connected to the same side of the writing module 300 that facesthe outer surface 308 of the insulating layer 108. As shown in theexample of FIG. 4, the discharging unit 402 can be a passive or activedevice that is dragged behind the ion head 304 along the surface 308.The discharging unit 402 removes negatively or positively charged ionsor charges from the surface 308 thereby reducing the likelihood thatduring handling of the e-paper 102 ions are redistributed on the surface308 causing a redistribution of white and black particles inmicrocapsules. For example, FIG. 4A shows a snapshot of the negativelycharged molecular ions 324 attached to the surface 308 after informationis written to the microcapsules 404 and 406 being removed from thesurface 308 by the discharging unit 402. In certain embodiments, apassive discharging unit 402 can be a rubber material that touches thesurface 308 as the e-paper 102 passes under the writing system 400.

In other embodiments, an active discharging unit 402 can be a chargedroller composed of a conductive rubber that removes charges from thesurface 308 as the roller passes over the surface 308. FIG. 4B shows aside view and schematic representation of an example writing system 410.The writing system 410 is similar to the writing system 400 except thedischarging unit 402 is a charged roller 412 that removes charges fromthe surface 308.

In other embodiments, the erasing unit 306 of the writing systems 300and 400 can be replaced by an AC or DC operated corona. FIG. 5 shows aside view and schematic representation of an example writing system 500.The writing system 500 is similar to the writing system 400 except theerasing unit 306 is replaced with a corona 502. In the example of FIG.5, the corona 502 is configured to generate a plasma of positivelycharged ionic species that migrate onto the surface 308 by convertingnaturally occurring gaseous molecules and atoms located in the air gapbetween the corona 502 and the surface 308 into positively charged ionsthat are deposited onto the surface 308. For example, in certainembodiments, the corona 502 can be configured to convert naturallyoccurring nitrogen (“N₂”) located in the air gap between the corona 502and the surface 308 into positively charged nitrogen gas ions (“N₂ ⁺”)that are deposited onto the surface 308. In other embodiments, thewriting module can be configured to inject molecules or atoms, such asN₂ or argon (“Ar”), into the corona 502, which in turn converts thecharge neutral molecules or atoms into positively charged ions that aredeposited onto the surface 308.

FIG. 5 also shows a snapshot of the e-paper 102 passing under the corona502 as positively charged ions 504 generated by the corona 502 migrateand are deposited onto the surface 308. As represented in microcapsule506, the positively charged ions attach to the surface 308 and createrepulsive electrostatic forces that drive the positively charged blackparticles away from the insulating layer 108 and create attractiveelectrostatic forces that drive negatively charged white particlestoward the insulating layer 108, erasing information contained inmicrocapsule 506. The ion head 304 is operated to selectively writeinformation into microcapsules by ejecting electrons 318 that change theions deposited on the surface 308 from positively charged ions intonegatively charged ions 508. For example, FIG. 5 shows a snapshot ofinformation being written to microcapsule 510. The negatively chargedions 508 attached to the surface 308 create repulsive electrostaticforces that drive the negatively charged white particles away from theinsulating layer 108 and create attractive electrostatic forces thatdrive positively charged black particles toward the insulating layer108. After information is written to the microcapsules, the e-paper 102continues to pass under the discharging unit 402, which removes thenegatively and positively charged ions from the surface 308.

In other embodiments, the corona 502 described above with reference toFIG. 5 can be used as a discharging unit 402. For example, thedischarging unit represented by the roller 412, shown in FIG. 4B, can bereplaced by an AC or DC operated corona that generates a plasma of anappropriate charge for removing charges or ions attached to the surface308.

For the sake of simplicity, the writing unit is described above ashaving only one ion head, but embodiments of the present invention arenot intended to be so limited. In practice, writing system embodimentscan be implemented with two or more ion heads. The ion heads can also beused to erase and write information to the e-paper. For example, a firstion head can be operated as an erasing unit and a second ion head can beoperated as described above to write information to the e-paper. Instill other embodiments, the ion head 304 can be replaced by one or moreneedles operated to supply a charge of an appropriate magnitude forwriting information to the microcapsule layer.

Writing system embodiments also include writing modules with an array ofelectrodes that face the surface 308 of the e-paper 102 and are used toerase information in a first pass of the e-paper and in a second pass ofthe e-paper the electrodes can be selectively operated to writeinformation to the e-paper 102. FIGS. 6A-6B show side views of a writingsystem 600. The writing system 600 includes a writing module 602 and aone-dimensional or two-dimensional array of electrodes 604. Eachelectrode in the array of electrodes can be individually operated inorder to selectively erase and writing information to the e-paper. Thewriting system 600 is oriented so that the electrodes face the surface308 of the e-paper 102. The writing system 600 can be operated by firsterasing the information stored in the e-paper followed by a second passthat selectively writes information to the e-paper 102. In FIG. 6A, thewriting system is operated to erase information stored in themicrocapsule layer by supplying a positive charge that drives positivelycharge black particles away from the insulating layer 108 and drivesnegatively charged white particles toward the insulating paper 108. InFIG. 6B, the writing system is operated to selectively write informationinto the layer of microcapsule 106 by supplying a negative charge thatattracts positively charge black particles toward the insulating layer108 and drives negatively charged white particles away from theinsulating paper 108. In other embodiments, the writing module 602 caninclude an erasing unit 306 and the array of electrodes 604 can beoperated to write information to the e-paper.

Writing systems also include writing modules with an array of electrodesthat can erase and write in a single pass. A portion of the electrodescan be dedicated to erasing while another portion of the electrodes canbe dedicated to writing information to the e-paper. FIG. 6C shows a sideview of a writing system 610. The writing system 610 includes thewriting module 602 and a one-dimensional or two-dimensional array ofindividually addressable electrodes 604. As shown in FIG. 6C, a firstportion of the electrodes 612 is operated to erase information stored inthe layer of microcapsules 106, and a second portion of electrodes 614is operated to write information to the layer of microcapsules 106. Notethat direction of motion can be sensed, and the operation of theelectrodes 604 can be dynamically changed to reduce motion directionsensitivity.

In other embodiments, the two-dimensional array of individuallyaddressable electrodes can be dimensioned to substantially match thedimensions of the e-paper, enabling the array of electrodes to erase andwrite to the entire e-paper without scanning. For example, thetwo-dimensional array of electrodes engages or contacts the e-paperperpendicular to the e-paper surface using a solenoid motor or othermechanical system.

The microcapsules 106 of the microcapsule layer can also be composed ofnegatively charged black particles and positively charged whiteparticles. In other embodiments, the writing system is operated to eraseinformation stored in the microcapsule layer by supplying a negativecharge that drives negatively charge black particles away from theinsulating layer 108 and attracts positively charged white particlestoward the insulating paper 108, and the writing system is operated toselectively write information into the microcapsule layer by supplying apositive charge that attracts negatively charge black particles towardthe insulating layer 108 and drives positively charged white particlesaway from the insulating paper 108.

The writing systems described above can be implemented in various kindsof printing systems. FIG. 7A shows an isometric view of an exampleprinting system 700. The printing system 700 includes a writing system702 mounted on two guide shafts 704 and 706 extending parallel to eachother. The writing system 702 is oriented with the erasing unit, ionheads, and discharging unit pointed toward e-paper 708. In the exampleshown in FIG. 7A, the shafts 704 and 706 extend through the writingmodule portion of the writing system 702. The writing system 702 can bemoved along the shafts 704 and 706 using a circular belt (not shown)attached to the writing module 710 and is driven by a motor (not shown).The writing system 702 is used to write information to the e-paper byraster scanning the writing system 702 back and forth as the writingsystem 702 is moved along the length of the e-paper 708. The writingsystem 702 moves back and forth along the shafts 704 and 706 asindicated by directional arrow 712. In certain embodiments, the printingsystem can be implemented by mounting the shafts 704 and 706 in ahousing that holds the shafts 704 and 706 stationary while the e-paper708 passes under the writing system 702 using a printer carriage (notshown) as indicated by directional arrow 714. In other embodiments, thee-paper can be held stationary while the shafts 704 and 706 are movedalong the length the e-paper, as indicated by directional arrow 716.

FIG. 7B shows a bottom view of the example writing system 702 revealingthe writing system 702 is composed of a staggered arrangement of fiveseparate ion heads 718 used to write information into the e-paper 708 asdescribed above with reference to FIGS. 3-5. The writing system 702 alsoincludes an erasing unit 720, as described above with reference to FIGS.3 and 4, and includes a discharging unit 722, as described above withreference to FIG. 4.

FIG. 7C shows a cross-sectional view of the printing system 700 inoperation along a line B-B, shown in FIG. 7A. The writing system 702 ismoved along the shafts 704 and 706 as the erasing unit 720, ion heads718, and discharging unit 722 are operated to write information into thee-paper 708, as described above with reference to FIGS. 3-4. In otherembodiments, the erasing unit can be a corona, as described above withreference to FIG. 5.

FIG. 8A shows an isometric view of an example printing system 800. Theprinting system 800 includes a writing system 802 attached to a guide804, both of which extend the width of e-paper 806. The writing system802 is oriented with the erasing unit, ion heads, and discharging unitpointed toward e-paper 806. The writing system 802 is configured towrite information to the e-paper 806 in a single pass. In certainembodiments, the e-paper 806 passes under the writing system 802 using aprinter carriage (not shown) as indicated by directional arrow 808. Inother embodiments, the e-paper 806 can be held stationary while thewriting system 802 is moved back and forth using a mechanized platformconnected to the guide 804, as indicated by directional arrow 810.

FIG. 8B shows a bottom view of the example writing system 802 revealingthe writing system 802 composed of an arrangement of separate ion heads812 that extend the length of the writing system 802. The arrangement ofion head 812 write information into the e-paper 806 in a single pass, asdescribed above with reference to FIGS. 3-5. The writing system 802 alsoincludes an erasing unit 814, as described above with reference to FIGS.3 and 4, and includes a discharging unit 816, as described above withreference to FIG. 4.

FIG. 8C shows a cross-sectional view of the printing system 800 inoperation along a line C-C, shown in FIG. 8A. As the writing system 802moves along the e-paper 806, the erasing unit 814, ion heads 812, anddischarging unit 816 write information into the e-paper 806 as describedabove with reference to FIGS. 3-4. In other embodiments, the erasingunit can be a corona, as described above with reference to FIG. 5.

The printing systems described above enable e-paper to be implemented ina variety of different non-electronic-based display platforms. Forexample, the paper 608 and 806 can be used in a variety of differentmedia, including posters, general signage, pricing labels, e-books. Inother embodiments, the display platform can be a card configured withone or more e-paper strips. The cards can be composed of a polyester, aplastic, or transparent Mylar in order to provide a substrate for theone or more e-paper strips, as described above with reference to FIGS.1-2.

FIGS. 9A-9B show just two examples of cards, each card configured with astrip of e-paper for displaying information. In the example of FIG. 9A,a card 902 can be a gift card or a card issued to customers of abusiness, such as a department store. The card 902 includes an e-paperstrip 904 and may include barcode or magnetic strip located on the backof the card (not shown), which is read by an electronic card machine.The card 902 can be issued value when the card 902 is sold to acustomer. This value can be stored on the card magnetic strip and/orstored in the business's database, which is linked to the card 902identification number. When the card 902 is issued and/or used, theamount can also be written on the e-paper strip 904. For example, asshown in FIG. 9A, the card 902 is sold by a business called “The CoffeeShop.” When the customer uses the card 902 to complete a transaction atThe Coffee Shop, the amount on the card is debited accordingly and theremaining amount of credit available 906 on the card is stored in thebusiness's database and is written to the e-paper strip 904. In this waythe customer does not have to remember the amount available on the cardafter each purchase. Instead, the amount available on the card isdisplayed on the e-paper strip 904 after each purchase. As shown in theexample of FIG. 9A, the e-paper strip 904 can also be used to displayadvertisements 908 or any other information.

In the example of FIG. 9B, a card 910 can be a security card issued by acompany or a government agency that wants to limit a visitor's access tocertain buildings or departments. The card 910 includes an e-paper strip912. When the card is issued to the wearer, the wearer's name and anyother relevant information can be written on the e-paper strip 912, sothat the wearer's access can be readily checked simply by reading theinformation displayed on the e-paper strip 912. For example, the e-paperstrip 912 includes the wearer's name 914, identifies the wearer as avisitor 916, indicates which building 918 the wearer has access to, andthe date 920 on which the wearer has access.

Display platforms are not intended to limited to the cards shown inFIGS. 9A-9B. The cards 902 and 910 are intended to represent just two ofthe many different kinds of uses for cards configured with one or moree-paper strips.

FIG. 10 shows an isometric view of an e-paper electronic writing machine1000 and a card 1002 configured with a strip of e-paper 1004. Themachine 1000 includes a slot 1006 for receiving 1008 and ejecting 1010the card 1002. The e-paper strip 1004 can be used to display a varietyof different types of written messages, as well as, images that can beread by the card holder. The machine 1000 includes a writing system,such as the writing systems 700 and 800. FIGS. 11A-11B show an exampleof the writing system 700 operated to write information to the e-paperstrip 1004 of the card 1002 inserted into the machine 1000. The writingsystem 700 can be operated to write information to the e-paper strip asdescribed above with reference to FIG. 7. When the writing system 700has completed writing information to the e-paper strip 1004, the card1002 is ejected from the machine 1000.

FIG. 12 shows a flow diagram of a method of writing information toelectronic paper. In step 1201, the electronic paper is passed under anerasing unit, which is configured to remove information stored in theelectronic paper as described above with reference to FIGS. 3 and 5. Instep 1202, the electronic paper is passed under one or more ion heads,which are configured to write information to the electronic paper asdescribed above with reference to FIG. 3. In step 1203, the electronicpaper is passed under a discharge unit configured to remove ionsattached the surface of the electronic paper, as described above withreference to FIG. 4.

The foregoing description, for purposes of explanation, used specificnomenclature to provide a thorough understanding of the invention.However, it will be apparent to one skilled in the art that the specificdetails are not required in order to practice the invention. Theforegoing descriptions of specific embodiments of the present inventionare presented for purposes of illustration and description. They are notintended to be exhaustive of or to limit the invention to the preciseforms disclosed. Obviously, many modifications and variations arepossible in view of the above teachings. The embodiments are shown anddescribed in order to best explain the principles of the invention andits practical applications, to thereby enable others skilled in the artto best utilize the invention and various embodiments with variousmodifications as are suited to the particular use contemplated.

1-20. (canceled)
 21. A device comprising: a module comprising a firstside spaced apart from and facing a first surface of a passive e-papermedia and comprising: an erasing unit to generate airborne electricalspecies having a first charge for attachment onto the first surface ofthe passive e-paper media to erase information in a fluid-containingmicrocapsule layer of the passive e-paper media; and a writing unit togenerate airborne electrical species having an opposite second chargefor attachment onto the first surface of the passive e-paper media towrite information in the fluid-containing microcapsule layer of thepassive e-paper media, wherein the erasing unit and the writing unit areboth positioned on the first side of the module and wherein relativemovement is to selectively occur between the module and the passivee-paper media during the erasing and the writing.
 22. The device ofclaim 21, wherein the module is stationary.
 23. The device of claim 21,wherein the erasing unit is in a leading position and the writing unitis in a trailing position spaced apart from the erasing unit.
 24. Thedevice of claim 21, wherein the erasing unit and the writing unit of themodule are both positioned to be vertically suspended above the passivee-paper media.
 25. The device of claim 21, comprising a ground nodeassociated with the imaging module and to be removably coupled relativeto an entire conductive ground layer of the passive e-paper media. 26.The device of claim 21, wherein at least the erasing unit comprises atleast one of a corona and an ion head.
 27. The device of claim 21,wherein the writing unit further comprises an ion head.
 28. The deviceof claim 21, wherein the module is configured to span the width of thepassive e-paper media to write information in a single pass.
 29. Thedevice of claim 21, comprising a housing containing the module andincluding a slot through which the passive e-paper media is to enter asa card to become aligned for relative movement relative to the moduleduring erasing and writing.
 30. The device of claim 29, wherein themodule is arranged to erase and write the information relative to apassive e-paper strip on the card.
 31. The device of claim 21, whereinthe module comprises a discharging unit in a trailing position relativeto the writing unit to discharge at least some ions from the firstsurface of the passive e-paper media.
 32. A method comprising: causingrelative movement between a writing module and a passive e-paper media,which comprises a charge-receiving layer, a charge-responsive,fluid-containing microcapsule layer, and a ground electrode; during suchrelative movement: erasing information in the microcapsule layer in thepassive e-paper media via first airborne electrical charges produced viaa first unit of the writing module; and writing information in themicrocapsule layer in the passive e-paper media via second airborneopposite electrical charges produced via a second unit of the writingmodule, wherein both the respective first and second units are locatedon a first side of the writing module to face a charge-receiving layerof the passive e-paper media.
 33. The method of claim 32, comprising:after writing information, removing at least some electrical chargesattached to the charge-receiving layer of the passive e-paper media viaa discharging unit associated with the writing module.
 34. The method ofclaim 32, comprising: positioning both the erasing unit and the writingunit to be vertically suspended above the passive e-paper media.
 35. Themethod of claim 34, comprising: arranging the erasing unit to include atleast one of a corona and an ion-head.
 36. The method of claim 32,comprising: arranging the writing unit to include an ion head tocomprise an ion head to eject electrons or ions.
 37. The method of claim32, wherein the module is stationary.
 38. The method of claim 32,coupling the entire ground electrode layer relative to a ground nodeduring the erasing and writing.
 39. The method of claim 32, comprisingperforming the coupling without applying power to the ground electrodelayer.
 40. The method of claim 32, comprising: arranging the passivee-paper media as a card; and initiating the relative movement viainserting the passive e-paper media card into a slot of a housing, whichcontains the writing module.